595 research outputs found
Olfactory Ensheathing Cell Tumor Arising from the Olfactory Mucosa
We report a rare case of olfactory ensheathing cell tumor. A female presented a large soft mass extending medially to the olfactory cleft and laterally to the middle meatus in the left nasal cavity. Imaging studies confirmed a cystic mass extending superiorly into the frontal lobe, indicating that the tumor arouse from the olfactory mucosa. A subtotal resection was achieved through an endoscopic endonasal approach without operative complications. Immunohistochemically constituent cells were diffusely positive for S-100 protein, but olfactory ensheathing cell tumor was diagnosed by negative staining for Leu7 (CD57). This case indicates that olfactory ensheathing cell tumor should be included in differential diagnoses for the olfactory cleft tumors
Compressive residual stress applied to a low-carbon steel surface alloyed with WC tool constituent elements according to friction stir processing
Yamamoto H., Yamamoto Y., Ito K., et al. Compressive residual stress applied to a low-carbon steel surface alloyed with WC tool constituent elements according to friction stir processing. Materials and Design 244, 113225 (2024); https://doi.org/10.1016/j.matdes.2024.113225.Friction stir processing (FSP) effectively improves the fatigue strength of arc-welded joints; however, wear of tools is inevitable in case of high-strength materials. Notably, a new benefit has been discovered: compressive residual stress is applied on the FSPed steel surface, alloyed with the WC tool constituent elements, contrasting with the tensile residual stress typically applied via conventional FSP. To elucidate the mechanism of compressive residual stress application, FSP was performed on a low-carbon steel plate at various rotational speeds. The alloyed topmost layers in the stir zone comprised martensite structures with a small amount of retained austenite grains, resulting in a hardness increase owing to the tool constituent elements. The residual stresses on the stir zone surface were influenced by the alloying contents and the corresponding martensite start temperature (Ms). Compressive residual stresses were maximized at an Ms of approximately 150 °C owing to martensitic transformation expansion near room temperature. Lowering the Ms below approximately 150 °C led to tensile residual stresses and an increased volume fraction of the retained austenite, suggesting that martensitic transformation expansion is insufficient to apply compressive residual stress. Conversely, the retained austenite can resist plastic deformation and crack propagation through deformation-induced martensitic transformation, thereby enhancing fatigue properties
Observations of Coherent Turbulence Structures in the Near-Neutral Atmospheric Boundary Layer
Turbulence structures of high Reynolds number flow in the near-neutral atmospheric boundary layer (ABL) are investigated based on observations at Shionomisaki and Shigaraki, Japan. A Doppler sodar measured the vertical profiles of winds in the ABL. Using the integral wavelet transform for the time series of surface wind data, the pattern of a descending high-speed structure with large vertical extent (from the surface to more than 200-m level) is depicted from the Doppler sodar data. Essentially this structure is a specific type of coherent structure that has been previously shown in experiments on turbulent boundary-layer flows. Large-scale high-speed structures in the ABL are extracted using a long time scale (240 s) for the wavelet transform. The non-dimensional interval of time between structures is evaluated as 3.0–6.2 in most cases. These structures make a large contribution to downward momentum transfer in the surface layer. Quadrant analyses of the turbulent motion measured by the sonic anemometer (20-m height) suggest that the sweep motion (high-speed downward motion) plays a substantial role in the downward momentum transfer. In general, the contribution of sweep motions to the momentum flux is nearly equal to that of ejection motions (low-speed upward motions). This contribution of sweep motions is related to the large-scale high-speed structures
Defects of Protein Phosphatase 2A Causes Corticosteroid Insensitivity in Severe Asthma
BACKGROUND: Corticosteroid insensitivity is a major barrier of treatment for some chronic inflammatory diseases, such as severe asthma, but the molecular mechanism of the insensitivity has not been fully elucidated. The object of this study is to investigate the role of protein phosphate 2A (PP2A), a serine/threonine phosphatase, on corticosteroid sensitivity in severe asthma. METHODOLOGY/PRINCIPAL FINDINGS: Corticosteroid sensitivity was determined by the dexamethasone ability to inhibit TNFα-induced IL-8 or LPS-induced TNFα production. PP2A expression, glucocorticoid receptor (GR) nuclear translocation defined as the nuclear/cytoplasmic GR ratio and phosphorylation of GR-Ser²²⁶, c-Jun N-terminal kinase 1 (JNK1) and PP2A were analysed by Western-blotting. Phosphatase activity was measured by fluorescence-based assay. Okadaic acid (OA), a PP2A inhibitor, reduced corticosteroid sensitivity with reduced GR nuclear translocation and increased GR phosphorylation in U937 monocytic cells. PP2A knockdown by RNA interference showed similar effects. IL-2/IL-4 treatment to U937 reduced corticosteroid sensitivity, and PP2A expression/activity. In peripheral blood mononuclear cells (PBMCs) from severe asthma, the PP2A expression and activity were significantly reduced with concomitant enhancement of PP2A(C)-Tyr³⁰⁷ phosphorylation compared with those in healthy volunteers. As the results, GR-Ser²²⁶ and JNK1 phosphorylation were increased. The expression and activity of PP2A were negatively correlated with phosphorylation levels of GR-Ser²²⁶. Furthermore, co-immunoprecipitation assay in U937 cells revealed that PP2A associated with GR and JNK1 and IL-2/IL-4 exposure caused dissociation of each molecule. Lastly, PP2A overexpression increased corticosteroid sensitivity in U937 cells. CONCLUSIONS/SIGNIFICANCE: PP2A regulates GR nuclear translocation and corticosteroid sensitivity possibly by dephosphorylation of GR-Ser²²⁶ via dephosphorylation of upstream JNK1. This novel mechanism will provide new insight for the development of new therapy for severe asthma
Graft Duodenal Perforation due to Internal Hernia after Simultaneous Pancreas-Kidney Transplantation: Report of a Case
Although complications including graft thrombosis, graft pancreatitis, and rejection have been well documented after pancreas transplantation, the occurrence of graft duodenal perforation is uncommon. In this article, we report a case of graft duodenal perforation due to internal hernia after simultaneous pancreas-kidney transplantation (SPK). A patient with type I diabetes mellitus and diabetic nephropathy had undergone SPK from a cadaveric donor. One year later, she was admitted to our hospital for severe lower abdominal pain with preshock status. She was immediately examined by abdominal computed tomography and both peripancreas graft fluid accumulation and severe dilatation of the ileum were detected. On emergency operation, two punched holes located at the graft duodenal side near the suture line and an obstruction of herniated bowel behind the graft pancreas were detected. These holes were repaired and the internal hernia was reduced. However, a control of the intraabdominal infection was very difficult despite intensive treatment with antibiotics and additional abdominal drainage. Finally, a graft pancreatectomy was unavoidably required. When complications, including symptomatic intraabdominal infection, require re-laparotomy after pancreas transplantation, the therapeutic focus should be switched from salvaging the graft to the preservation of life
Nephrin is an important component of the barrier system in the testis.
Nephrin, a gene product of the congenital nephrotic syndrome of the Finnish type (NPHS1), is a 1242-residue putative transmembrane protein of the immunoglobulin family of cell adhesion molecules. The expression of this gene is localized in rat and human glomerular epithelial cells. Here we report the expression of nephrin in various tissues other than the kidneys in mice. The expression of nephrin mRNA in various tissues of mice, including the kidneys, testes, spleen, thymus and brain, were first investigated by the RT-PCR method, and it was shown that a high level of nephrin mRNA could be detected in the testes of mice 1-6 weeks old. In situ hybridization revealed the expression of the nephrin gene in the Sertoli cells. Additionally, immunofluorescent staining studies indicated that nephrin was colocalized with anchoring protein ZO-1 in the mouse testis. From these results, it is inferred that nephrin is an important component of the barrier system in testes.</p
Defects in ZnO nanoparticles laser-ablated in water-ethanol mixtures at different pressures
The effect of liquid medium and its pressure on the photoluminescence of ZnO nanoparticles prepared via laser ablation of Zn targets in various water-ethanol mixtures is studied. As the ethanol content increases, the photoluminescence of the product changes, while metallic zinc is observed to emerge in nanomaterials prepared in ethanol-rich environments. The applied pressure had a less profound effect, mainly affecting materials produced in water or water-ethanol, and much less those generated in pressurized ethanol. Tuning the reactivity of the liquid and pressurizing it during laser ablation is demonstrated to be promising for tailoring the emission properties of the product
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